Random access channel (RACH) transmission with cross-band downlink/uplink (DL/UL) pairing

ABSTRACT

Wireless communications systems and methods related to performing random channel access are provided. A first wireless communication device communicates a random access configuration with a second wireless communication device in a first frequency spectrum. The random access configuration includes information associated with a channel characteristic difference between the first frequency spectrum and the second frequency spectrum. The first wireless communication device communicates a random access signal with the second wireless communication device in the second frequency spectrum based on the random access configuration. The first frequency spectrum is a millimeter wave (mmWav) frequency band. The second frequency spectrum is a non-mmWav frequency band.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S.Non-Provisional patent application Ser. No. 16/058,678 filed Aug. 8,2018, which claims priority to and the benefit of the U.S. ProvisionalPatent Application No. 62/548,204, filed Aug. 21, 2017, each of which ishereby incorporated by reference in its entirety as if fully set forthbelow and for all applicable purposes.

TECHNICAL FIELD

This application relates to wireless communication systems and methods,and more particularly to performing a random access procedure in anetwork that employs a millimeter wave (mmWav) band for downlink (DL)communications and a non-mmWav band for uplink (UL) communications.

INTRODUCTION

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). A wirelessmultiple-access communications system may include a number of basestations (BSs), each simultaneously supporting communication formultiple communication devices, which may be otherwise known as userequipment (UE). The communication direction from a BS to a UE isreferred to as DL. The communication direction from a UE to a BS isreferred to as UL. To meet the growing demands for expanded mobilebroadband connectivity, wireless communication technologies areadvancing from the LTE technology to a next generation new radio (NR)technology. One technique for expanding connectivity may be to extendthe frequency operation range to higher frequencies since lowerfrequencies are becoming over-crowded. For example, mmWav frequencybands between about 30 gigahertz (GHz) to about 300 GHz can provide alarge bandwidth for high data rate communications. However,transmissions in the mmWav frequencies may have potential health impactsto human bodies. One approach to avoiding or minimizing the effects ofmmWav to human bodies may be to use mmWav frequencies for DLcommunications, but continue to use low frequencies (e.g., at sub-6 GHz)for UL communications. As such, UL transmissions, which may typicallyoriginate from a UE located close to a user, may remain in the lowfrequencies. In addition, the pairing of a DL mmWav band with a UL sub-6GHz band can minimize implementation complexity at the UEs. While thepairing of a DL mmWav band with a UL sub-6 GHz band can improveconnectivity, the different channel characteristics between a mmWav bandand a sub-6 GHz band can be cause challenges for initial network access.

BRIEF SUMMARY OF SOME EXAMPLES

The following summarizes some aspects of the present disclosure toprovide a basic understanding of the discussed technology. This summaryis not an extensive overview of all contemplated features of thedisclosure, and is intended neither to identify key or critical elementsof all aspects of the disclosure nor to delineate the scope of any orall aspects of the disclosure. Its sole purpose is to present someconcepts of one or more aspects of the disclosure in summary form as aprelude to the more detailed description that is presented later.

For example, in an aspect of the disclosure, a method of wirelesscommunication includes communicating, by a first wireless communicationdevice with a second wireless communication device, a random accessconfiguration including information associated with a channelcharacteristic difference between a first frequency spectrum and asecond frequency spectrum, the random access configuration communicatedin the first frequency spectrum; and communicating, by the firstwireless communication device with the second wireless communicationdevice, a random access signal in the second frequency spectrum based onthe random access configuration.

In an additional aspect of the disclosure, an apparatus including atransceiver configured to communicate, with a second wirelesscommunication device, a random access configuration includinginformation associated with a channel characteristic difference betweena first frequency spectrum and a second frequency spectrum, the randomaccess configuration communicated in the first frequency spectrum; andcommunicate, with the second wireless communication device, a randomaccess signal in the second frequency spectrum based on the randomaccess configuration.

In an additional aspect of the disclosure, a computer-readable mediumhaving program code recorded thereon, the program code includes code forcausing a first wireless communication device to communicate, with asecond wireless communication device, a random access configurationincluding information associated with a channel characteristicdifference between a first frequency spectrum and a second frequencyspectrum, the random access configuration communicated in the firstfrequency spectrum; and code for causing the first wirelesscommunication device to communicate, with the second wirelesscommunication device, a random access signal in the second frequencyspectrum based on the random access configuration.

Other aspects, features, and embodiments of the present invention willbecome apparent to those of ordinary skill in the art, upon reviewingthe following description of specific, exemplary embodiments of thepresent invention in conjunction with the accompanying figures. Whilefeatures of the present invention may be discussed relative to certainembodiments and figures below, all embodiments of the present inventioncan include one or more of the advantageous features discussed herein.In other words, while one or more embodiments may be discussed as havingcertain advantageous features, one or more of such features may also beused in accordance with the various embodiments of the inventiondiscussed herein. In similar fashion, while exemplary embodiments may bediscussed below as device, system, or method embodiments it should beunderstood that such exemplary embodiments can be implemented in variousdevices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a wireless communication network according toembodiments of the present disclosure.

FIG. 2 illustrates a cross-band downlink/uplink (DL/UL) pairing scenarioaccording to embodiments of the present disclosure.

FIG. 3 illustrates a signaling diagram of a random access method in anetwork using cross-band DL/UL pairing according to embodiments of thepresent disclosure.

FIG. 4 is a block diagram of an exemplary user equipment (UE) accordingto embodiments of the present disclosure.

FIG. 5 is a block diagram of an exemplary base station (BS) according toembodiments of the present disclosure.

FIG. 6 illustrates a signaling diagram of a random access method with apower adjustment for cross-band DL/UL pairing according to embodimentsof the present disclosure.

FIG. 7 illustrates a signaling diagram of a random access method with apower adjustment for cross-band DL/UL pairing according to embodimentsof the present disclosure.

FIG. 8 illustrates a signaling diagram of a random access method withadditional DL transmissions in an uplink (UL) band to facilitatecross-band DL/UL pairing according to embodiments of the presentdisclosure.

FIG. 9 is a flow diagram of a random access method with a poweradjustment for cross-band DL/UL pairing according to embodiments of thepresent disclosure.

FIG. 10 is a flow diagram of a random access method with additional DLtransmissions in a UL band to facilitate cross-band DL/UL pairingaccording to embodiments of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with theappended drawings, is intended as a description of variousconfigurations and is not intended to represent the only configurationsin which the concepts described herein may be practiced. The detaileddescription includes specific details for the purpose of providing athorough understanding of the various concepts. However, it will beapparent to those skilled in the art that these concepts may bepracticed without these specific details. In some instances, well-knownstructures and components are shown in block diagram form in order toavoid obscuring such concepts.

The techniques described herein may be used for various wirelesscommunication networks such as code-division multiple access (CDMA),time-division multiple access (TDMA), frequency-division multiple access(FDMA), orthogonal frequency-division multiple access (OFDMA),single-carrier FDMA (SC-FDMA) and other networks. The terms “network”and “system” are often used interchangeably. A CDMA network mayimplement a radio technology such as Universal Terrestrial Radio Access(UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and othervariants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856 standards. ATDMA network may implement a radio technology such as Global System forMobile Communications (GSM). An OFDMA network may implement a radiotechnology such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB),IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc.UTRA and E-UTRA are part of Universal Mobile Telecommunication System(UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are newreleases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSMare described in documents from an organization named “3rd GenerationPartnership Project” (3GPP). CDMA2000 and UMB are described in documentsfrom an organization named “3rd Generation Partnership Project 2”(3GPP2). The techniques described herein may be used for the wirelessnetworks and radio technologies mentioned above as well as otherwireless networks and radio technologies, such as a next generation(e.g., 5^(th) Generation (5G) operating in mmWave bands) network.

To facilitate synchronization in a network, a base station (BS) maybroadcast synchronization signal blocks (SSBs) periodically in thenetwork. The SSBs may include synchronization signals, systeminformation signals, and/or other reference signals. A UE may listen tothe network and synchronizes to the BS based on the SSBs. The UE mayinitiate a network access by transmitting a random access request signalin a random access channel (RACH). In some instances, the RACH may be acontention-based RACH, where multiple users or UEs may access the sameresource. The random access request signal may include a predeterminedpreamble. The UE may perform open loop power control to determine atransmission power level for transmitting the random access requestsignal. For example, the BS may broadcast a transmission power levelused for SSB transmissions and an initial target random access receptionpower desired at the BS. Thus, the UE may estimate a path loss in the DLchannel based on a reception power of the SSBs measured at the UE andthe SSB transmission power level indicated in the SSBs. The UE maydetermine the transmission power level based on the DL path loss and theinitial target random access reception power.

In a network where a DL frequency band and a UL frequency band havesimilar channel characteristics, the DL path loss may be similar to theUL path loss. Thus, the determination of an initial random accesstransmission power level based on the DL path loss may provide asufficiently good performance. However, when a network pairs a DL mmWavband with a UL sub-6 GHz band, where the DL path loss may besignificantly different from the UL path loss, the determination of aninitial random access transmission power level based on the DL path lossmay not provide a good performance.

The present application describes mechanisms for performing a randomaccess procedure in a network with cross-band DL/UL pairing. Forexample, a network may employ a mmWav band for DL communications and aUL non-mmWav band, such as a sub-6 GHz band, for UL communications. Thedisclosed embodiments consider the different channel characteristicsbetween the DL mmWav band and the UL non-mmWav band for random accesspower control. For example, the disclosed embodiments may consider thedifferent path loss and/or the different penetration loss between the DLmmWav band and the UL non-mmWav band and/or the different antenna arraygains or compensations that a BS may apply to communications in the DLmmWav band and the UL non-mmWav band.

In an embodiment, a BS may determine an initial target random accessreception power desired at the BS. The BS may apply an adjustment to theinitial target random access reception power to account for thedifferent channel characteristics between the DL mmWav band and the ULnon-mmWav band. The BS may indicate the initial target random accessreception power including the adjustment in a DL broadcast signal (e.g.,an SSB). Thus, the channel characteristic difference or the adjustmentmay be transparent to a UE.

In another embodiment, the BS may indicate an initial target randomaccess reception power desired at the BS without the adjustment in a DLbroadcast signal (e.g., an SSB). In addition, the BS may indicateadjustment parameters in the DL broadcast signal to enable the UE toaccount for the different channel characteristics between the DL mmWavband and the UL non-mmWav band during a random access transmission powerlevel determination.

In yet another embodiment, the BS may additionally transmit low-dutycycle measurement signals in the UL non-mmWav band to enable the UE toestimate channel characteristics in the UL non-mmWav band. The BS mayindicate the transmission power level of the measurement signals. Thus,the UE may listen to the network in the DL mmWav band and in the ULnon-mmWav band. For example, the UE may receive the transmission powerlevel of the measurement signals from the DL mmWav band and themeasurement signals from the UL non-mmWav band. The UE may determine arandom access transmission power level based on a path loss estimatedfrom the measurement signal. In some embodiments, the measurementsignals may include SSBs or other suitable reference signals. In someembodiments, the BS may transmit the measurement signals in the ULnon-mmWav band based on frequency-division multiplexing (FDM) ortime-division multiplexing (TDM) with UL signals.

Aspects of the present application can provide several benefits. Forexample, the inclusion of the adjustment at the BS or the indication ofthe adjustment parameters to the UE allows the UE to determine a moresuitable or random access transmission power in a network withcross-band DL/UL pairing, and thus may improve random accessperformance. The additional measurement signal transmissions in the ULnon-mmWav band allows the UE to obtain a more accurate estimate ofchannel characteristics in the UL non-mmWav band, and thus may furtherimprove random access performance. While the disclosed embodiments aredescribed in the context of a network deployed over a DL mmWav band anda UL non-mmWav band, the disclosed embodiments can be applied to anetwork deployed over any pair of DL/UL bands with significantlydifferent channel characteristics. For example, the DL band may belocated at significantly higher frequencies than the UL band.

FIG. 1 illustrates a wireless communication network 100 according toembodiments of the present disclosure. The network 100 includes BSs 105,UEs 115, and a core network 130. In some embodiments, the network 100operates over a shared spectrum. The shared spectrum may be unlicensedor partially licensed to one or more network operators. Access to thespectrum may be limited and may be controlled by a separate coordinationentity. In some embodiments, the network 100 may be a LTE or LTE-Anetwork. In yet other embodiments, the network 100 may be a millimeterwave (mmW) network, a new radio (NR) network, a 5G network, or any othersuccessor network to LTE. The network 100 may be operated by more thanone network operator. Wireless resources may be partitioned andarbitrated among the different network operators for coordinatedcommunication between the network operators over the network 100.

The BSs 105 may wirelessly communicate with the UEs 115 via one or moreBS antennas. Each BS 105 may provide communication coverage for arespective geographic coverage area 110. In 3GPP, the term “cell” canrefer to this particular geographic coverage area of a BS and/or a BSsubsystem serving the coverage area, depending on the context in whichthe term is used. In this regard, a BS 105 may provide communicationcoverage for a macro cell, a pico cell, a femto cell, and/or other typesof cell. A macro cell generally covers a relatively large geographicarea (e.g., several kilometers in radius) and may allow unrestrictedaccess by UEs with service subscriptions with the network provider. Apico cell may generally cover a relatively smaller geographic area andmay allow unrestricted access by UEs with service subscriptions with thenetwork provider. A femto cell may also generally cover a relativelysmall geographic area (e.g., a home) and, in addition to unrestrictedaccess, may also provide restricted access by UEs having an associationwith the femto cell (e.g., UEs in a closed subscriber group (CSG), UEsfor users in the home, and the like). A BS for a macro cell may bereferred to as a macro BS. A BS for a pico cell may be referred to as apico BS. A BS for a femto cell may be referred to as a femto BS or ahome BS. In the example shown in FIG. 1 , the BSs 105 a, 105 b and 105 care examples of macro BSs for the coverage areas 110 a, 110 b and 110 c,respectively. The BSs 105 d is an example of a pico BS or a femto BS forthe coverage area 110 d. As will be recognized, a BS 105 may support oneor multiple (e.g., two, three, four, and the like) cells.

Communication links 125 shown in the network 100 may include uplink (UL)transmissions from a UE 115 to a BS 105, or downlink (DL) transmissions,from a BS 105 to a UE 115. The UEs 115 may be dispersed throughout thenetwork 100, and each UE 115 may be stationary or mobile. A UE 115 mayalso be referred to as a mobile station, a subscriber station, a mobileunit, a subscriber unit, a wireless unit, a remote unit, a mobiledevice, a wireless device, a wireless communications device, a remotedevice, a mobile subscriber station, an access terminal, a mobileterminal, a wireless terminal, a remote terminal, a handset, a useragent, a mobile client, a client, or some other suitable terminology. AUE 115 may also be a cellular phone, a personal digital assistant (PDA),a wireless modem, a wireless communication device, a handheld device, atablet computer, a laptop computer, a cordless phone, a personalelectronic device, a handheld device, a personal computer, a wirelesslocal loop (WLL) station, an Internet of things (IoT) device, anInternet of Everything (IoE) device, a machine type communication (MTC)device, an appliance, an automobile, or the like.

The BSs 105 may communicate with the core network 130 and with oneanother. The core network 130 may provide user authentication, accessauthorization, tracking, Internet Protocol (IP) connectivity, and otheraccess, routing, or mobility functions. At least some of the BSs 105(e.g., which may be an example of an evolved NodeB (eNB), a nextgeneration NodeB (gNB), or an access node controller (ANC)) mayinterface with the core network 130 through backhaul links 132 (e.g.,S1, S2, etc.) and may perform radio configuration and scheduling forcommunication with the UEs 115. In various examples, the BSs 105 maycommunicate, either directly or indirectly (e.g., through core network130), with each other over backhaul links 134 (e.g., X1,X2, etc.), whichmay be wired or wireless communication links.

Each BS 105 may also communicate with a number of UEs 115 through anumber of other BSs 105, where the BS 105 may be an example of a smartradio head. In alternative configurations, various functions of each BS105 may be distributed across various BSs 105 (e.g., radio heads andaccess network controllers) or consolidated into a single BS 105. Insome implementations, the network 100 utilizes orthogonal frequencydivision multiplexing (OFDM) on the downlink and single-carrierfrequency division multiplexing (SC-FDM) on the UL. OFDM and SC-FDMpartition the system bandwidth into multiple (K) orthogonal subcarriers,which are also commonly referred to as tones, bins, or the like. Eachsubcarrier may be modulated with data. In general, modulation symbolsare sent in the frequency domain with OFDM and in the time domain withSC-FDM. The spacing between adjacent subcarriers may be fixed, and thetotal number of subcarriers (K) may be dependent on the systembandwidth. The system bandwidth may also be partitioned into subbands.

In an embodiment, the BSs 105 can assign or schedule transmissionresources (e.g., in the form of time-frequency resource blocks) for DLand UL transmissions in the network 100. The communication can be in theform of radio frames. A radio frame may be divided into a plurality ofsubframes, for example, about 10. Each subframe can be divided intoslots, for example, about 2. Each slot may be further divided intomini-slots. In a frequency-division duplexing (FDD) mode, simultaneousUL and DL transmissions may occur in different frequency bands. Forexample, each subframe includes a UL subframe in a UL frequency band anda DL subframe in a DL frequency band. In a time-division duplexing (TDD)mode, UL and DL transmissions occur at different time periods using thesame frequency band. For example, a subset of the subframes (e.g., DLsubframes) in a radio frame may be used for DL transmissions and anothersubset of the subframes (e.g., UL subframes) in the radio frame may beused for UL transmissions.

The DL subframes and the UL subframes can be further divided intoseveral regions. For example, each DL or UL subframe may havepre-defined regions for transmissions of reference signals, controlinformation, and data. Reference signals are predetermined signals thatfacilitate the communications between the BSs 105 and the UEs 115. Forexample, a reference signal can have a particular pilot pattern orstructure, where pilot tones may span across an operational bandwidth orfrequency band, each positioned at a pre-defined time and a pre-definedfrequency. For example, a BS 105 may transmit cell specific referencesignals (CRSs) and/or channel state information—reference signals(CSI-RSs) to enable a UE 115 to estimate a DL channel. Similarly, a UE115 may transmit sounding reference signals (SRSs) to enable a BS 105 toestimate a UL channel. Control information may include resourceassignments and protocol controls. Data may include protocol data and/oroperational data. In some embodiments, the BSs 105 and the UEs 115 maycommunicate using self-contained subframes. A self-contained subframemay include a portion for DL communication and a portion for ULcommunication. A self-contained subframe can be DL-centric orUL-centric. A DL-centric subframe may include a longer duration for DLcommunication than UL communication. A UL-centric subframe may include alonger duration for UL communication than UL communication.

In an embodiment, a UE 115 attempting to access the network 100 mayperform an initial cell search by detecting a primary synchronizationsignal (PSS) from a BS 105. The PSS may enable synchronization of periodtiming and may indicate a physical layer identity value. The UE 115 maythen receive a secondary synchronization signal (SSS). The SSS mayenable radio frame synchronization, and may provide a cell identityvalue, which may be combined with the physical layer identity value toidentify the cell. The SSS may also enable detection of a duplexing modeand a cyclic prefix length. Some systems, such as TDD systems, maytransmit an SSS but not a PSS. Both the PSS and the SSS may be locatedin a central portion of a carrier, respectively.

After receiving the PSS and SSS, the UE 115 may receive a masterinformation block (MIB), which may be transmitted in the physicalbroadcast channel (PBCH). The MIB may contain system bandwidthinformation, a system frame number (SFN), and a Physical Hybrid-ARQIndicator Channel (PHICH) configuration. After decoding the MIB, the UE115 may receive one or more system information blocks (SIBs). Forexample, SIB1 may contain cell access parameters and schedulinginformation for other SIBs. Decoding SIB1 may enable the UE 115 toreceive SIB2. SIB2 may contain radio resource configuration (RRC)configuration information related to random access channel (RACH)procedures, paging, physical uplink control channel (PUCCH), physicaluplink shared channel (PUSCH), power control, SRS, and cell barring.After obtaining the MIB and/or the SIBs, the UE 115 can perform randomaccess procedures to establish a connection with the BS 105. Afterestablishing the connection, the UE 115 and the BS 105 can enter anormal operation stage, where operational data may be exchanged.

In an embodiment, the network 100 may employ cross-band DL/UL pairing toimprove data throughput. For example, the network 100 may employ ahigh-frequency mmWav band for DL communications and a low-frequencynon-mmWav band in sub-6 GHz frequencies for UL communications. Forexample, the DL mmWav band may have a significantly higher path lossthan the UL non-mmWav band. To overcome the high path loss, the BSs 105may employ beamforming (e.g., analog and/or digital beamforming) togenerate narrow beams directing towards certain directions for DLcommunications with the UEs 115. To facilitate initial channel accesspower control at the UEs 115, the BSs 105 may provide informationrelated to channel characteristics of the DL mmWav band and the ULnon-mmWav band, as described in greater detail herein.

FIG. 2 illustrates a cross-band DL/UL pairing scenario 200 according toembodiments of the present disclosure. In FIG. 2 , the x-axis representsfrequency in some constant units. The scenario 200 may correspond to acommunication scenario between a BS 105 and a UE 115 in the network 100.The scenario 200 includes a frequency spectrum B 206 and a frequencyspectrum A 208. The frequency spectrum A 208 is located in a mmWavfrequency band 204, for example, at frequencies above 10 GHz. Thefrequency spectrum B 206 is located in a low-frequency nom-mmWavfrequency band 202, for example, at sub-6 GHz frequencies. The spectrumA 208 may be used for DL communications 220. For example, a BS 105 maysend a DL communication signal to a UE 115 in the spectrum A 208. Thespectrum B 206 may be used for UL communications 210. For example, a UE115 may send a UL communication signal to a BS 105 in the spectrum B206. The DL channel path or channel response in the frequency spectrum A208 may significantly differ from the UL channel path or channelresponse in the frequency spectrum B 206. For example, the path lossand/or the penetration loss may be higher in frequency spectrum A 208than in the frequency spectrum B 206 due to the high frequencies. Inaddition, the BS 105 may employ different antenna array gains orcompensations for the DL communications 220 in the frequency spectrum A208 and the UL communications 210 in the frequency spectrum B 206.

FIG. 3 illustrates a signaling diagram of a random access method 300 ina network using cross-band DL/UL pairing according to embodiments of thepresent disclosure. The network may be similar to the network 100 andemploy cross-band DL/UL pairing as shown in the scenario 200. The method300 is implemented between a BS such as the BS 105 and a UE such as theUE 115 during an initial channel access. As illustrated, the method 300includes a number of enumerated steps, but embodiments of the method 300may include additional steps before, after, and in between theenumerated steps. In some embodiments, one or more of the enumeratedsteps may be omitted or performed in a different order. The method 300illustrates one BS and one UE for purposes of simplicity of discussion,though it will be recognized that embodiments of the present disclosuremay scale to many more UEs and/or BSs.

At step 305, the BS broadcasts SSBs in a frequency spectrum A (e.g., themmWav frequency spectrum A 208). The BS may transmit the SSBs usingmultiple narrow beams in multiple beam directions, for example, byemploying analog and/or digital beamforming. The BS may transmit theSSBs repeatedly at a predetermined periodicity. The SSBs may includePSSs, SSSs, PBCH signals, and/or any reference signal that mayfacilitate cell or channel synchronization at the UE. A PSS or an SSSmay include a predetermined sequence for channel synchronization. A PBCHsignal may carry cell access related information, channel configurationinformation, SSB configuration information, physical random accesschannel (PRACH) configuration information, and/or neighboring cellinformation. The channel configuration information may includebandwidths, frequency bands (e.g., the frequency spectrums 206 and 208),and/or numerologies (e.g., subcarrier spacing) for UL and DLcommunications. The SSB configuration information may indicate SSBperiodicities and/or an SSB transmission power level. The PRACHconfiguration information may indicate sequences, formats, resources, aninitial target random access reception power level at the BS, and/orother information for random access preamble transmissions.

At step 310, the UE listens to the network for SSBs. The UE may receivemultiple SSBs from the BS in one or more beam directions. The UE maydetermine reception powers of the received SSBs and select a preferredSSB or beam direction based on the reception powers. For example, the UEmay select the SSB with the maximum reception power. The UE maydetermine a path loss in the frequency spectrum A based on thedetermined reception power and the SSB transmission power levelbroadcast in the SSB configuration information. The UE may determine aninitial random access transmission power level based on the determinedpath loss and the initial target random access reception power level.However, the frequency spectrum A and the frequency spectrum B may havedifferent channel characteristics (e.g., path loss) due to the differentfrequency ranges. Thus, the BS and/or the UE may need to account for thechannel characteristic difference, as described in greater detailherein.

At step 315, the UE transmits a random access request in a frequencyspectrum B (e.g., the low-frequency non-mmWav frequency spectrum B 206).The UE may generate a random access preamble according to the PRACHconfiguration information (e.g., the sequence and format information).The UE may transmit the random access request in the form of a signalcarrying the random access preamble. The UE may transmit the randomaccess request using the determined random access transmission powerlevel.

At step 320, after transmitting the random access request, the UEmonitors for a random access response from the BS in the frequencyspectrum A, for example, during a random access response window.

At step 325, upon detecting the random access request, the BS determinesthe UL transmission timing associated with the UE and assigns a resourcein the frequency B to the UE.

At step 330, the BS transmits a random access response to the UE in thefrequency spectrum A, for example, using a narrow beam. The randomaccess response may include UL timing adjustment information, theallocation of the resource in the frequency spectrum B, and any otherinformation (e.g., a temporary identifier for the UE) for subsequentconnection establishment.

At step 335, upon receiving the random access response, the UE transmitsa connection request according to the random access response, forexample, using the assigned resource in the frequency spectrum B.

At step 340, upon receiving the connection request, the BS may respondby transmitting a connection response in the frequency spectrum A. Theconnection response may provide configuration information specific tothe UE.

In some embodiments, the random access request and the connectionrequest transmitted in the frequency spectrum B may use one subcarrierspacing and the random access response and the connection responsetransmitted in the frequency spectrum A may use another subcarrierspacing. The start and/or end of random access response window used forrandom access response monitoring in the step 320 may be defined basedon the UL subcarrier spacing in the frequency spectrum B or may bedefined using a time duration (e.g., in milliseconds (ms) or seconds).In some embodiments, the random access request, the random, accessresponse, the connection request, and the connection response may bereferred to as message 1, message 2, message 3, and message 4,respectively.

FIG. 4 is a block diagram of an exemplary UE 400 according toembodiments of the present disclosure. The UE 400 may be a UE 115 asdiscussed above. As shown, the UE 400 may include a processor 402, amemory 404, a random access module 408, a transceiver 410 including amodem subsystem 412 and a radio frequency (RF) unit 414, and one or moreantennas 416. These elements may be in direct or indirect communicationwith each other, for example via one or more buses.

The processor 402 may include a central processing unit (CPU), a digitalsignal processor (DSP), an application specific integrated circuit(ASIC), a controller, a field programmable gate array (FPGA) device,another hardware device, a firmware device, or any combination thereofconfigured to perform the operations described herein. The processor 402may also be implemented as a combination of computing devices, e.g., acombination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration.

The memory 404 may include a cache memory (e.g., a cache memory of theprocessor 402), random access memory (RAM), magnetoresistive RAM (MRAM),read-only memory (ROM), programmable read-only memory (PROM), erasableprogrammable read only memory (EPROM), electrically erasableprogrammable read only memory (EEPROM), flash memory, solid state memorydevice, hard disk drives, other forms of volatile and non-volatilememory, or a combination of different types of memory. In an embodiment,the memory 404 includes a non-transitory computer-readable medium. Thememory 404 may store instructions 406. The instructions 406 may includeinstructions that, when executed by the processor 402, cause theprocessor 402 to perform the operations described herein with referenceto the UEs 115 in connection with embodiments of the present disclosure.Instructions 406 may also be referred to as code. The terms“instructions” and “code” should be interpreted broadly to include anytype of computer-readable statement(s). For example, the terms“instructions” and “code” may refer to one or more programs, routines,sub-routines, functions, procedures, etc. “Instructions” and “code” mayinclude a single computer-readable statement or many computer-readablestatements.

The random access module 408 may be implemented via hardware, software,or combinations thereof. For example, the random access module 408 maybe implemented as a processor, circuit, and/or instructions 406 storedin the memory 404 and executed by the processor 402. The random accessmodule 408 may be used for various aspects of the present disclosure.For example, the random access module 408 is configured to synchronizeto a BS (e.g., the BSs 105) in a network (e.g., the network 100),initiate network access, and/or perform random access power controlbased on different channel characteristics in UL and DL frequencyspectrums (e.g., the spectrums 206 and 208), as described in greaterdetail herein.

As shown, the transceiver 410 may include the modem subsystem 412 andthe RF unit 414. The transceiver 410 can be configured to communicatebi-directionally with other devices, such as the BSs 105. The modemsubsystem 412 may be configured to modulate and/or encode the data fromthe memory 404, and/or the random access module 408 according to amodulation and coding scheme (MCS), e.g., a low-density parity check(LDPC) coding scheme, a turbo coding scheme, a convolutional codingscheme, a digital beamforming scheme, etc. The RF unit 414 may beconfigured to process (e.g., perform analog to digital conversion ordigital to analog conversion, etc.) modulated/encoded data from themodem subsystem 412 (on outbound transmissions) or of transmissionsoriginating from another source such as a UE 115 or a BS 105. The RFunit 414 may be further configured to perform analog beamforming inconjunction with the digital beamforming. Although shown as integratedtogether in transceiver 410, the modem subsystem 412 and the RF unit 414may be separate devices that are coupled together at the UE 115 toenable the UE 115 to communicate with other devices.

The RF unit 414 may provide the modulated and/or processed data, e.g.data packets (or, more generally, data messages that may contain one ormore data packets and other information), to the antennas 416 fortransmission to one or more other devices. This may include, forexample, transmission of random access signals for initial networkattachment according to embodiments of the present disclosure. Theantennas 416 may further receive data messages transmitted from otherdevices. This may include, for example, reception of discovery signalssuch as PSSs, SSSs, PBCH signals, discovery reference signals, and/orSSBs according to embodiments of the present disclosure. The antennas416 may provide the received data messages for processing and/ordemodulation at the transceiver 410. The antennas 416 may includemultiple antennas of similar or different designs in order to sustainmultiple transmission links. The RF unit 414 may configure the antennas416.

FIG. 5 is a block diagram of an exemplary BS 500 according toembodiments of the present disclosure. The BS 500 may be a BS 105 asdiscussed above. A shown, the BS 500 may include a processor 502, amemory 504, a random access module 508, a transceiver 510 including amodem subsystem 512 and a RF unit 514, and one or more antennas 516.These elements may be in direct or indirect communication with eachother, for example via one or more buses.

The processor 502 may have various features as a specific-typeprocessor. For example, these may include a CPU, a DSP, an ASIC, acontroller, a FPGA device, another hardware device, a firmware device,or any combination thereof configured to perform the operationsdescribed herein. The processor 502 may also be implemented as acombination of computing devices, e.g., a combination of a DSP and amicroprocessor, a plurality of microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration.

The memory 504 may include a cache memory (e.g., a cache memory of theprocessor 502), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, asolid state memory device, one or more hard disk drives, memristor-basedarrays, other forms of volatile and non-volatile memory, or acombination of different types of memory. In some embodiments, thememory 504 may include a non-transitory computer-readable medium. Thememory 504 may store instructions 506. The instructions 506 may includeinstructions that, when executed by the processor 502, cause theprocessor 502 to perform operations described herein. Instructions 506may also be referred to as code, which may be interpreted broadly toinclude any type of computer-readable statement(s) as discussed abovewith respect to FIG. 5 .

The random access module 508 may be implemented via hardware, software,or combinations thereof. For example, the random access module 508 maybe implemented as a processor, circuit, and/or instructions 506 storedin the memory 504 and executed by the processor 502. The random accessmodule 508 may be used for various aspects of the present disclosure.For example, the random access module 508 is configured to transmit SSBsincluding PRACH configurations to facilitate initial network access in anetwork (e.g., the network 100) using cross-band DL/UL pairing (e.g., asshown in the scenario 200), as described in greater detail herein.

As shown, the transceiver 510 may include the modem subsystem 512 andthe RF unit 514. The transceiver 510 can be configured to communicatebi-directionally with other devices, such as the UEs 115 and/or anothercore network element. The modem subsystem 512 may be configured tomodulate and/or encode data according to a MCS, e.g., a LDPC codingscheme, a turbo coding scheme, a convolutional coding scheme, a digitalbeamforming scheme, etc. The RF unit 514 may be configured to process(e.g., perform analog to digital conversion or digital to analogconversion, etc.) modulated/encoded data from the modem subsystem 512(on outbound transmissions) or of transmissions originating from anothersource such as a UE 115 or 400. The RF unit 514 may be furtherconfigured to perform analog beamforming and/or digital beamforming fordirectional signal transmissions and/or receptions. In some embodiments,the transceiver 510 may include antenna array elements and/ortransceiver components (e.g., power amplifiers) that can be switched onor off to form a beam in a particular direction. Alternatively, thetransceiver 510 may include multiple transmit/receive chains and mayswitch between the multiple transmit/receive chains to form a beam in aparticular direction. In some embodiments, the antenna array elementsmay be different or configured differently for UL and DL paths. Thus, ULand DL may have different antenna array gains. Although shown asintegrated together in transceiver 510, the modem subsystem 512 and theRF unit 514 may be separate devices that are coupled together at the BS105 to enable the BS 105 to communicate with other devices.

The RF unit 514 may provide the modulated and/or processed data, e.g.data packets (or, more generally, data messages that may contain one ormore data packets and other information), to the antennas 516 fortransmission to one or more other devices. This may include, forexample, transmission of information to complete attachment to a networkand communication with a camped UE 115 or 400 according to embodimentsof the present disclosure. The antennas 516 may further receive datamessages transmitted from other devices and provide the received datamessages for processing and/or demodulation at the transceiver 510. Theantennas 516 may include multiple antennas of similar or differentdesigns in order to sustain multiple transmission links.

FIG. 6 illustrates a signaling diagram of a random access method 600with a power adjustment for cross-band DL/UL pairing according toembodiments of the present disclosure. The method 600 may be implementedbetween a BS such as the BS 105 and 500 and a UE such as the UEs 115 and400. The method 600 may use similar random access mechanisms asdescribed in the method 300 with respect to FIG. 3 . The method 600provides a more detailed view of the mechanisms for a BS to account forchannel characteristic differences between a UL band (e.g., thefrequency spectrum B 206) and a DL band (e.g., the frequency spectrum A208) when using cross-band DL/UL pairing as shown in the scenario 200.As illustrated, the method 600 includes a number of enumerated steps,but embodiments of the method 600 may include additional steps before,after, and in between the enumerated steps. In some embodiments, one ormore of the enumerated steps may be omitted or performed in a differentorder. The method 600 illustrates one BS and one UE for purposes ofsimplicity of discussion, though it will be recognized that embodimentsof the present disclosure may scale to many more UEs and/or BSs.

In the method 600, the BS communicates DL communications (e.g., the DLcommunications 220) with the UE in a frequency spectrum A (e.g., thefrequency spectrum A 208) and communicates UL communications (e.g., theUL communications 210) with the UE in a frequency spectrum B (e.g., thefrequency spectrum B 206).

At step 610, the BS adjusts an initial target reception power forinitial random access. For example, the BS may determine an initialtarget reception power of a random access signal desired at the BS. TheBS may determine a power adjustment for the initial target receptionpower based on channel characteristic differences between the frequencyspectrum A and the frequency spectrum B.

For example, the BS may adjust the initial target reception power by apenetration loss difference between the frequency spectrum A and thefrequency spectrum B, a path loss difference between the frequencyspectrum A and the frequency spectrum B, an antenna array gaindifference between communications in the frequency spectrum A and thefrequency spectrum B, and/or any other parameters related to channelpath differences. Penetration loss may refer to the signal levelattenuation or fading caused by an obstruction (e.g., a wall or abuilding). Path loss may refer to the signal level attenuation caused byfree-space propagation, reflection, diffraction, scattering, and/orabsorption (e.g., penetration). Path loss may include a factor dependenton the carrier or center frequency of a transmission (e.g., between ammWav frequency and a sub-6 GHz frequency). Antenna array gain may referto the power gain of a transmitted signal using multiple antennas. Forexample, the BS may employ different antenna array elements (e.g.,elements in the transceiver 510) or configure antenna array elementsdifferently for UL and DL communications. In an embodiment, the BS maycompute the power adjustment as shown below:Adjustment=P _(delta_e)+20×log₁₀(f _(UL) /f _(DL))+AG _(delta)  (1)where P_(delta_e) represents the penetration loss difference between thefrequency spectrum A and the frequency spectrum B based on a nominal ULtransmission and a nominal DL transmission, 20×log₁₀(f_(UL)/f_(DL))represents the frequency dependency factor contributing to the path lossdifference between the frequency spectrum A and the frequency spectrumB, f_(DL) represents the center frequency of the frequency spectrum A,f_(UL) represents the center frequency of the frequency spectrum B, andAG_(delta) represents the antenna array gain difference used for UL andDL communications. The BS may adjust the initial target reception powerlevel by adding the adjustment to the initial target reception powerlevel.

At step 620, the BS transmits a configuration in the frequency spectrumA. The configuration may indicate the initial target reception powerlevel including the adjustment shown in Equation (1).

At step 630, the BS transmits SSBs or DL broadcast signals in thefrequency spectrum A, for example, in different beam directions. TheSSBs or the DL broadcast signals may include information indicatingtransmission power level used by the BS to transmit the SSBs or the DLbroadcast signals. In some embodiments, the configuration in the step620 may be included in system information carried in a PBCH signalwithin an SSB.

At step 640, the UE determines a path loss for the spectrum A based on adifference between a reception power of a selected SSB at the UE and anSSB transmission power level used by the BS. At step 650, the UEdetermines a transmission power level for transmitting a random accessrequest signal based on the determined path loss. For example, the UEmay compute the transmission power level as shown below:P _(PRACH)=min{P _(CMAX) ,P _(target) +P _(L)}  (2)where P_(PRACH) represents the random access transmission power level,min represents a minimum operator, P_(CMAX) represents the maximumtransmit power level allowable at the UE, P_(target) represents theinitial target reception power level at the BS, and P_(L) represents thepath loss in the frequency spectrum A.

At step 660, the UE transmits a random access request signal in thefrequency spectrum B using the determined random access transmissionpower level shown in Equation (2). Subsequently, the BS and the UE mayexchange a random access response, a connection request, and aconnection response to complete the initial channel access as shown inthe method 300.

As can be seen in the method 600, the BS includes the adjustment in theinitial target reception power level transmitted to the UE. Thus, thechannel characteristic difference may be transparent to the UE, wherethe random access transmission power level may be computed as shown inEquation (2) without an additional power adjustment offset. FIG. 7illustrates a signaling diagram of a random access method 700 with apower adjustment for cross-band DL/UL pairing according to embodimentsof the present disclosure. The method 700 may be implemented between aBS such as the BS 105 and 500 and a UE such as the UEs 115 and 400. Themethod 700 may be similar to method 600, but the UE may account forchannel characteristic differences between a UL band (e.g., thefrequency spectrum B 206) and a DL band (e.g., the frequency spectrum A208) when using cross-band DL/UL pairing as shown in the scenario 200instead of the BS. As illustrated, the method 700 includes a number ofenumerated steps, but embodiments of the method 700 may includeadditional steps before, after, and in between the enumerated steps. Insome embodiments, one or more of the enumerated steps may be omitted orperformed in a different order. The method 700 illustrates one BS andone UE for purposes of simplicity of discussion, though it will berecognized that embodiments of the present disclosure may scale to manymore UEs and/or BSs.

Similar to the method 600, the BS communicates DL communications (e.g.,the DL communications 220) with the UE in a frequency spectrum A (e.g.,the frequency spectrum A 208) and communicates UL communications (e.g.,the UL communications 210) with the UE in a frequency spectrum B (e.g.,the frequency spectrum B 206).

At step 710, the BS determines adjustment parameters for random accesspower control at the UE based on channel characteristic differencesbetween the frequency spectrum A and the frequency spectrum B. Forexample, the BS may determine a penetration loss adjustment parameterbased on the penetration loss difference between the frequency spectrumA and the frequency spectrum B. In addition, the BS may determine anantenna array gain adjustment parameter based on the different antennaarray gains at the BS's transmitter and the BS's receiver. The BS mayfurther determine other parameters associated with the different channelpaths between a DL communication (e.g., the DL communications 220) and aUL communication (e.g., the UL communications 210).

At step 720, the BS transmits a configuration in the frequency spectrumA. The configuration may indicate the penetration loss adjustmentparameter, the antenna array gain adjustment parameter, and/or aninitial target random access reception power level at the BS.

At step 730, the BS transmits SSBs or DL broadcast signals in thefrequency spectrum A, for example, in different beam directions. TheSSBs or the DL broadcast signals may indicate a transmission power levelused by the BS to transmit the SSBs or the DL broadcast signals. In someembodiments, the configuration in the step 720 may be included in a PBCHsignal or a system information block (SIB).

At step 740, the UE determines a path loss for the spectrum A based on adifference between a reception power of a selected SSB at the UE and anSSB transmission power level used by the BS. At step 750, the UEdetermines a transmission power level for transmitting a random accessrequest signal based on the determined path loss. At step 755, the UEadjusts the transmission power level based on the adjustment parameters.For example, the UE may compute the transmission power level as shownbelow:P _(RACH)=min{P _(CMAX) ,P _(target) +P _(delta_e)+20×log₁₀(f _(UL) /f_(DL))+AG _(delta) +P _(L)}  (3)

At step 760, the UE transmits a random access signal in the frequencyspectrum B using the determined random access transmission power levelshown in Equation (3). Subsequently, the BS and the UE may exchange arandom access response, a connection request, and a connection responseto complete the initial channel access as shown in the method 300.

As can be seen in the method 700, the BS provides the adjustmentparameters to the UE and the UE computes the random access transmissionpower level by incorporating the adjustment parameters. While themethods 600 and 700 account for the channel characteristic differencesbetween the frequency spectrum A and the frequency spectrum B, thepenetration loss difference is based on nominal DL and nominal ULtransmissions and the antenna array gain difference is based onestimates of the BS. The UE may experience a different penetration lossand/or a different antenna array gain as estimated by the BS. Thus, theadjustment parameters may not be sufficient or accurate in representingthe channel characteristic differences between the frequency spectrum Aand the frequency spectrum B.

FIG. 8 illustrates a signaling diagram of a random channel access method800 with additional DL transmissions in a UL band to facilitatecross-band DL/UL pairing according to embodiments of the presentdisclosure. The method 800 may be implemented between a BS such as theBS 105 and 500 and a UE such as the UEs 115 and 400. The method 800 mayuse similar random access mechanisms as described in the method 300 withrespect to FIG. 3 , but the BS may additionally transmit communicationsignals in a UL frequency band (e.g., the frequency spectrum B 206) toallow the UE to measure channel characteristics in the UL frequency bandfor random access power control when using cross-band DL/UL pairing asshown in the scenario 200. As illustrated, the method 800 includes anumber of enumerated steps, but embodiments of the method 800 mayinclude additional steps before, after, and in between the enumeratedsteps. In some embodiments, one or more of the enumerated steps may beomitted or performed in a different order. The method 800 illustratesone BS and one UE for purposes of simplicity of discussion, though itwill be recognized that embodiments of the present disclosure may scaleto many more UEs and/or BSs.

Similar to the methods 600 and 700, the BS communicates DLcommunications (e.g., the DL communications 220) with the UE in afrequency spectrum A (e.g., the frequency spectrum A 208) andcommunicates UL communications (e.g., the UL communications 210) withthe UE in a frequency spectrum B (e.g., the frequency spectrum B 206).In addition, the BS transmits measurement signals in the frequencyspectrum B.

At step 810, the BS determines an initial target reception power of arandom access signal desired at the BS.

At step 820, the BS transmits a measurement signal in the frequencyspectrum B to allow the UE to determine channel characteristics in thefrequency spectrum B. The measurement signal may include an SSB or anysuitable reference signal (e.g., including a predetermined sequence)that may facilitate channel measurements. The BS may transmit themeasurement signal repeatedly with a large periodicity (e.g., at aboutevery 10 ms, 20 ms, 40 ms, 80 ms, or 100 ms). The BS may transmit themeasurement signal using FDM and/or TDM with the UL communications.

At step 830, the BS transmits a configuration in the frequency spectrumA. The configuration may indicate an initial target random accessreception power level at the BS. The configuration may additionallyindicate a transmission power level used for transmitting themeasurement signal. In some embodiments, the BS may transmit SSBs or DLbroadcast signals including the configuration.

At step 840, the UE determines a path loss for the frequency spectrum Bbased on a difference between a reception power of the measurementsignal at the UE and the transmission power level of the measurementsignal indicated in the configuration.

At step 850, the UE determines a transmission power level fortransmitting a random access request signal in the frequency spectrum Bbased on the determined path loss. For example, the UE may compute thetransmission power level as shown above in Equation (2).

At step 860, the UE transmits a random access signal in the frequencyspectrum B using the transmission power level determined in the step850. Subsequently, the BS and the UE may exchange a random accessresponse, a connection request, and a connection response to completethe initial channel access as shown in the method 300.

Since the UE can estimate the channel response of the frequency spectrumB based on a signal received from the frequency spectrum B instead ofbased on adjustment parameters estimated by the BS, the method 800 mayallow for more accurate random access transmission power determinationsand improve random access performance. However, in the method 800, theBS is required to additionally support transmit capability in thefrequency spectrum B and the UE is required to additionally supportreceive capability in the frequency spectrum B.

FIG. 9 is a flow diagram of a random access method 900 with a poweradjustment for cross-band DL/UL pairing according to embodiments of thepresent disclosure. Steps of the method 900 can be executed by acomputing device (e.g., a processor, processing circuit, and/or othersuitable component) of a wireless communication device, such as the BSs105 and 500 and the UEs 115 and 400. The method 900 may employ similarmechanisms as in the scenario 200 and the methods 300, 600, and 700 asdescribed with respect to FIGS. 2, 3, 6, and 7 , respectively. Asillustrated, the method 900 includes a number of enumerated steps, butembodiments of the method 900 may include additional steps before,after, and in between the enumerated steps. In some embodiments, one ormore of the enumerated steps may be omitted or performed in a differentorder.

At step 910, the method 900 includes communicating, by a first wirelesscommunication device with a second wireless communication device, arandom access configuration in a first frequency spectrum. The randomaccess configuration may include information associated with a channelcharacteristic difference between the first frequency spectrum and asecond frequency spectrum. The first frequency spectrum may be similarto the frequency spectrum A 208 located at a mmWav band 204. The secondfrequency spectrum may be similar to the frequency spectrum B 206located at a non-mmWav band 202 (e.g., a sub-6 GHz band). In general,the first frequency spectrum may be located at higher frequencies thanthe second frequency spectrum. For example, the first frequency spectrumcan be in a frequency range between about 1-2 GHz, about 2-3 GHz, about3-4 GHz, about 4-5 GHz, or about 5-6 GHz, and the second frequencyspectrum can be in a frequency range between about 600-700 MHz, about700-800 MHz, or about 800-900 MHz. The channel characteristic differencemay include a penetration loss difference between the first frequencyspectrum and the second frequency spectrum, a path loss differencebetween the first frequency spectrum and the second frequency spectrum,and/or an antenna array gain difference between communications in thefirst frequency spectrum and the second frequency spectrum.

At step 920, the method 900 includes communicating, by the firstwireless communication device with the second wireless communicationdevice, a communication signal in the first frequency spectrum. Thecommunication signal may be an SSB signal. The communication signal mayindicate a transmission power level of the communication signal. In someembodiments, the communication signal may include an SSB signal or aPBCH signal or a SIB including the random access configuration.

At step 930, the method 900 includes communicating, by the firstwireless communication device with the second wireless communicationdevice, a random access signal in the second frequency spectrum based onthe communication signal and the random access configuration. The randomaccess signal may include a random access preamble sequence.

In an embodiment, the first wireless communication device may correspondto a BS and the second wireless communication device may correspond to aUE. In such an embodiment, the first wireless communication device maytransmit the random access configuration and the communication signal tothe second wireless communication device and may receive the randomaccess signal from the second wireless communication device. In oneembodiment, the first wireless communication device may determine atarget reception power level of the random access signal at the firstwireless communication device and adjusts the target reception powerlevel according to Equation (1) as shown in the method 600. The randomaccess configuration may indicate the adjusted target reception powerlevel. In another embodiment, the first wireless communication devicemay determine an adjustment parameter for power control at the secondwireless communication device based on the channel characteristicdifference and indicate the adjustment parameter in the random accessconfiguration as shown in the method 700.

In another embodiment, the first wireless communication device maycorrespond to a UE and the second wireless communication device maycorrespond to a BS. In such an embodiment, the first wirelesscommunication device may receive the random access configuration and thecommunication signal from the second wireless communication device andmay transmit the random access signal to the second wirelesscommunication device. In one embodiment, the random access configurationmay indicate a target reception power level at the second wirelesscommunication device and the first wireless communication device maydetermine a transmission power level for transmitting the random accesssignal based on a path loss in the first frequency spectrum (e.g.,computed based on a reception power of the communication signal and thetransmission power level of the communication signal) and the targetreception power level. In some embodiments, the random accessconfiguration may further indicate an adjustment parameter for thechannel characteristic difference. In such embodiments, the firstwireless communication device may determine the transmission power levelfurther based on the adjustment parameter according to Equation (3) asshown in the method 700.

FIG. 10 is a flow diagram of a random access method 1000 with additionalDL transmissions in a UL band to facilitate cross-band DL/UL pairingaccording to embodiments of the present disclosure. Steps of the method1000 can be executed by a computing device (e.g., a processor,processing circuit, and/or other suitable component) of a wirelesscommunication device, such as the BSs 105 and 500 and the UEs 115 and400. The method 1000 may employ similar mechanisms as in the scenario200 and the methods 300 and 800 as described with respect to FIGS. 2, 3,and 8 , respectively. As illustrated, the method 1000 includes a numberof enumerated steps, but embodiments of the method 1000 may includeadditional steps before, after, and in between the enumerated steps. Insome embodiments, one or more of the enumerated steps may be omitted orperformed in a different order.

At step 1010, the method 1000 includes communicating, by a firstwireless communication device with a second wireless communicationdevice, a random access configuration in a first frequency spectrum. Thefirst frequency spectrum may be similar to the frequency spectrum A 208located at a mmWav band 204.

At step 1020, the method 1000 includes communicating, by the firstwireless communication device with the second wireless communicationdevice, a communication signal in a second frequency spectrum. Thecommunication signal may be an SSB signal. In some embodiments, thecommunication signal may include an SSB signal or a measurementreference signal. The second frequency spectrum may be similar to thefrequency spectrum B 206 located at a non-mmWav band 202 (e.g., a sub-6GHz band). The random access configuration may indicate a transmissionpower level of the communication signal communicated in the secondfrequency spectrum.

At step 1030, the method 1000 includes communicating, by the firstwireless communication device with the second wireless communicationdevice, a random access signal in the second frequency spectrum based onthe communication signal and the random access configuration. The randomaccess signal may include a random access preamble sequence.

In an embodiment, the first wireless communication device may correspondto a BS and the second wireless communication device may correspond to aUE. In such an embodiment, the first wireless communication device maytransmit the random access configuration and the communication signal tothe second wireless communication device and may receive the randomaccess signal from the second wireless communication device. The randomaccess configuration may further indicate a target reception power levelof the random access signal at the first wireless communication device.

In an embodiment, the first wireless communication device may correspondto a UE and the second wireless communication device may correspond to aBS. In such an embodiment, the first wireless communication device mayreceive the random access configuration and the communication signalfrom the second wireless communication device and may transmit therandom access signal to the second wireless communication device. Therandom access configuration may further indicate a target receptionpower level of the random access signal at the second wirelesscommunication device. The first wireless communication device maydetermine a transmission power level for transmitting the random accesssignal based on the target reception power level for the random accesssignal, the reception power of the communication signal measured at thefirst wireless communication device, and the transmission power level ofthe communication signal.

Information and signals may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the above description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, an FPGA or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. A general-purpose processor may be a microprocessor,but in the alternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices (e.g., a combinationof a DSP and a microprocessor, multiple microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described above can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations. Also, as used herein, including in the claims, “or” as usedin a list of items (for example, a list of items prefaced by a phrasesuch as “at least one of” or “one or more of”) indicates an inclusivelist such that, for example, a list of [at least one of A, B, or C]means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

Embodiments of the present disclosure include a method of wirelesscommunication, comprising communicating, by a first wirelesscommunication device with a second wireless communication device, arandom access configuration including information associated with achannel characteristic difference between a first frequency spectrum anda second frequency spectrum, the random access configurationcommunicated in the first frequency spectrum; and communicating, by thefirst wireless communication device with the second wirelesscommunication device, a random access signal in the second frequencyspectrum based on the random access configuration.

In some embodiments, wherein the channel characteristic differenceincludes at least one of a penetration loss difference between the firstfrequency spectrum and the second frequency spectrum, a path lossdifference between the first frequency spectrum and the second frequencyspectrum, or an antenna array gain difference between communications inthe first frequency spectrum and the second frequency spectrum. In someembodiments, wherein the communicating the random access configurationincludes transmitting, by the first wireless communication device to thesecond wireless communication device, the random access configuration,and wherein the communicating the random access signal includesreceiving, by the first wireless communication device from the secondwireless communication device, the random access signal. In someembodiments, the method further comprises determining, by the firstwireless communication device, a target reception power level of therandom access signal at the first wireless communication device based onthe channel characteristic difference, wherein the random accessconfiguration indicates the target reception power level. In someembodiments, the method further comprises determining, by the firstwireless communication device, an adjustment parameter for power controlat the second wireless communication device based on the channelcharacteristic difference, wherein the random access configurationindicates at least the adjustment parameter. In some embodiments,wherein the communicating the random access configuration includesreceiving, by the first wireless communication device from the secondwireless communication device, the random access configuration, andwherein the communicating the random access signal includestransmitting, by the first wireless communication device to the secondwireless communication device, the random access signal at atransmission power level based on the random access configuration. Insome embodiments, wherein the random access configuration indicates atarget reception power level at the second wireless communicationdevice, and wherein the method further comprises determining, by thefirst wireless communication device, the transmission power level basedon at least the target reception power level. In some embodiments,wherein the random access configuration further indicates an adjustmentparameter for the channel characteristic difference, and wherein thedetermining is further based on the adjustment parameter. In someembodiments, the method further comprises communicating, by the firstwireless communication device with the second wireless communicationdevice, a random access response in the first frequency spectrum inresponse to the random access signal; communicating, by the firstwireless communication device with the second wireless communicationdevice, a connection request in the second frequency spectrum inresponse to the random access response; and communicating, by the firstwireless communication device with the second wireless communicationdevice, a connection response in the first frequency spectrum inresponse to the connection request. In some embodiments, the methodfurther comprises communicating, by the first wireless communicationdevice with the second wireless communication device, a firstcommunication signal on a first subcarrier spacing in the firstfrequency spectrum; and communicating, by the first wirelesscommunication device with the second wireless communication device, asecond communication signal based on a second subcarrier spacing in thesecond frequency spectrum, wherein the first subcarrier spacing and thesecond subcarrier spacing are different. In some embodiments, whereinthe first frequency spectrum is at a millimeter wave band. In someembodiments, wherein the second frequency spectrum is at anon-millimeter wave band.

Embodiments of the present disclosure include a method of wirelesscommunication, comprising communicating, by a first wirelesscommunication device with a second wireless communication device, arandom access configuration for a first frequency spectrum, the randomaccess configuration communicated in a second frequency spectrumdifferent from first frequency spectrum; communicating, by the firstwireless communication device with the second wireless communicationdevice, a communication signal in the first frequency spectrum based onthe random access configuration; and communicating, by the firstwireless communication device with the second wireless communicationdevice, a random access signal in the first frequency spectrum based onthe communication signal.

In some embodiments, wherein the random access configuration indicatesat least a transmission power level of the communication signal, andwherein the communication signal includes at least one of asynchronization signal or a reference signal. In some embodiments,wherein the communicating the random access configuration includestransmitting, by the first wireless communication device to the secondwireless communication device, the random access configuration; thecommunicating the communication signal includes transmitting, by thefirst wireless communication device to the second wireless communicationdevice, the communication signal based on the transmission power level;and the communicating the random access signal includes receiving, bythe first wireless communication device from the second wirelesscommunication device, the random access signal. In some embodiments,wherein the communicating the random access configuration includesreceiving, by the first wireless communication device from the secondwireless communication device, the random access configuration; thecommunicating the communication signal includes receiving, by the firstwireless communication device from the second wireless communicationdevice, the communication signal; and the communicating the randomaccess signal includes transmitting, by the first wireless communicationdevice to the second wireless communication device, the random accesssignal based on a transmission power level determined based on at leasta reception power of the communication signal at the first wirelesscommunication device and the transmission power level of thecommunication signal.

Embodiments of the present disclosure include an apparatus comprising atransceiver configured to communicate, with a second wirelesscommunication device, a random access configuration includinginformation associated with a channel characteristic difference betweena first frequency spectrum and a second frequency spectrum, the randomaccess configuration communicated in the first frequency spectrum; andcommunicate, with the second wireless communication device, a randomaccess signal in the second frequency spectrum based on the randomaccess configuration.

In some embodiments, wherein the channel characteristic differenceincludes at least one of a penetration loss difference between the firstfrequency spectrum and the second frequency spectrum, a path lossdifference between the first frequency spectrum and the second frequencyspectrum, or an antenna array gain difference between communications inthe first frequency spectrum and the second frequency spectrum. In someembodiments, wherein the transceiver is further configured tocommunicate the random access configuration by transmitting, to thesecond wireless communication device, the random access configuration;and communicate the random access signal by receiving, from the secondwireless communication device, the random access signal. In someembodiments, the apparatus further comprises a processor configured todetermine a target reception power level of the random access signal atthe apparatus based on the channel characteristic difference, whereinthe random access configuration indicates the target reception powerlevel. In some embodiments, the apparatus further comprises a processorconfigured to determine an adjustment parameter for power control at thesecond wireless communication device based on the channel characteristicdifference, wherein the random access configuration indicates at leastthe adjustment parameter. In some embodiments, wherein the transceiveris further configured to communicate the random access configuration byreceiving, from the second wireless communication device, the randomaccess configuration; and communicate the random access signal bytransmitting, to the second wireless communication device, the randomaccess signal at a transmission power level based on the random accessconfiguration. In some embodiments, wherein the random accessconfiguration indicates a target reception power level at the secondwireless communication device, and wherein the apparatus furthercomprises a processor configured to determine the transmission powerlevel based on at least the target reception power level. In someembodiments, wherein the random access configuration further indicatesan adjustment parameter for the channel characteristic difference, andwherein the processor is further configured to determine thetransmission power level further based on the adjustment parameter. Insome embodiments, wherein the transceiver is further configured tocommunicate, with the second wireless communication device, a randomaccess response in the first frequency spectrum in response to therandom access signal; communicate, with the second wirelesscommunication device, a connection request in the second frequencyspectrum in response to the random access response; and communicate,with the second wireless communication device, a connection response inthe first frequency spectrum in response to the connection request. Insome embodiments, wherein the transceiver is further configured tocommunicate, with the second wireless communication device, a firstcommunication signal on a first subcarrier spacing in the firstfrequency spectrum; and communicate, with the second wirelesscommunication device, a second communication signal based on a secondsubcarrier spacing in the second frequency spectrum, wherein the firstsubcarrier spacing and the second subcarrier spacing are different. Insome embodiments, wherein the first frequency spectrum is at amillimeter wave band. In some embodiments, wherein the second frequencyspectrum is at a non-millimeter wave band.

Embodiments of the present disclosure include an apparatus comprising atransceiver configured to communicate, with a second wirelesscommunication device, a random access configuration for a firstfrequency spectrum, the random access configuration communicated in asecond frequency spectrum different from first frequency spectrum;communicate, with the second wireless communication device, acommunication signal in the first frequency spectrum based on the randomaccess configuration; and communicate, with the second wirelesscommunication device, a random access signal in the first frequencyspectrum based on the communication signal.

In some embodiments, wherein the random access configuration indicatesat least a transmission power level of the communication signal, andwherein the communication signal includes at least one of asynchronization signal or a reference signal. In some embodiments,wherein the transceiver is further configured to communicate the randomaccess configuration by transmitting, to the second wirelesscommunication device, the random access configuration; communicate thecommunication signal by transmitting, to the second wirelesscommunication device, the communication signal based on the transmissionpower level; and communicate the random access signal by receiving, fromthe second wireless communication device, the random access signal. Insome embodiments, wherein the transceiver is further configured tocommunicate the random access configuration by receiving, from thesecond wireless communication device, the random access configuration;communicate the communication signal by receiving, from the secondwireless communication device, the communication signal; and communicatethe random access signal by transmitting, to the second wirelesscommunication device, the random access signal based on a transmissionpower level determined based on at least a reception power of thecommunication signal at the apparatus and the transmission power levelof the communication signal.

Embodiments of the present disclosure include a computer-readable mediumhaving program code recorded thereon, the program code comprising codefor causing a first wireless communication device to communicate, with asecond wireless communication device, a random access configurationincluding information associated with a channel characteristicdifference between a first frequency spectrum and a second frequencyspectrum, the random access configuration communicated in the firstfrequency spectrum; and code for causing the first wirelesscommunication device to communicate, with the second wirelesscommunication device, a random access signal in the second frequencyspectrum based on the random access configuration.

In some embodiments, wherein the channel characteristic differenceincludes at least one of a penetration loss difference between the firstfrequency spectrum and the second frequency spectrum, a path lossdifference between the first frequency spectrum and the second frequencyspectrum, or an antenna array gain difference between communications inthe first frequency spectrum and the second frequency spectrum. In someembodiments, wherein the code for causing the first wirelesscommunication device to communicate the random access configuration isfurther configured to transmit, to the second wireless communicationdevice, the random access configuration, and wherein the code forcausing the first wireless communication device to communicate therandom access signal is further configured to receive, from the secondwireless communication device, the random access signal. In someembodiments, the computer-readable medium further comprises code forcausing the first wireless communication device to determine a targetreception power level of the random access signal at the first wirelesscommunication device based on the channel characteristic difference,wherein the random access configuration indicates the target receptionpower level. In some embodiments, the computer-readable medium furthercomprises code for causing the first wireless communication device todetermine an adjustment parameter for power control at the secondwireless communication device based on the channel characteristicdifference, wherein the random access configuration indicates at leastthe adjustment parameter. In some embodiments, wherein the code forcausing the first wireless communication device to communicate therandom access configuration is further configured to receive, from thesecond wireless communication device, the random access configuration,and wherein the code for causing the first wireless communication deviceto communicate the random access signal is further configured totransmit, to the second wireless communication device, the random accesssignal at a transmission power level based on the random accessconfiguration. In some embodiments, wherein the random accessconfiguration indicates a target reception power level at the secondwireless communication device, and wherein the computer-readable mediumfurther comprises code for causing the first wireless communicationdevice to determine the transmission power level based on at least thetarget reception power level. In some embodiments, wherein the randomaccess configuration further indicates an adjustment parameter for thechannel characteristic difference, and wherein the code for causing thefirst wireless communication device to determine the transmission powerlevel is further configured to determine the transmission power levelfurther based on the adjustment parameter. In some embodiments, thecomputer-readable medium further comprises code for causing the firstwireless communication device to communicate, with the second wirelesscommunication device, a random access response in the first frequencyspectrum in response to the random access signal; code for causing thefirst wireless communication device to communicate, with the secondwireless communication device, a connection request in the secondfrequency spectrum in response to the random access response; and codefor causing the first wireless communication device to communicate, withthe second wireless communication device, a connection response in thefirst frequency spectrum in response to the connection request. In someembodiments, the computer-readable medium further comprises code forcausing the first wireless communication device to communicate, with thesecond wireless communication device, a first communication signal on afirst subcarrier spacing in the first frequency spectrum; and code forcausing the first wireless communication device to communicate, with thesecond wireless communication device, a second communication signalbased on a second subcarrier spacing in the second frequency spectrum,wherein the first subcarrier spacing and the second subcarrier spacingare different. In some embodiments, wherein the first frequency spectrumis at a millimeter wave band. In some embodiments, wherein the secondfrequency spectrum is at a non-millimeter wave band.

Embodiments of the present disclosure include a computer-readable mediumhaving program code recorded thereon, the program code comprising codefor causing a first wireless communication device to communicate, with asecond wireless communication device, a random access configuration fora first frequency spectrum, the random access configuration communicatedin a second frequency spectrum different from first frequency spectrum;code for causing the first wireless communication device to communicate,with the second wireless communication device, a communication signal inthe first frequency spectrum based on the random access configuration;and code for causing the first wireless communication device tocommunicate, with the second wireless communication device, a randomaccess signal in the first frequency spectrum based on the communicationsignal.

In some embodiments, wherein the random access configuration indicatesat least a transmission power level of the communication signal, andwherein the communication signal includes at least one of asynchronization signal or a reference signal. In some embodiments,wherein the code for causing the first wireless communication device tocommunicate the random access configuration is further configured totransmit, to the second wireless communication device, the random accessconfiguration; the code for causing the first wireless communicationdevice to communicate the communication signal is further configured totransmit, to the second wireless communication device, the communicationsignal based on the transmission power level; and the code for causingthe first wireless communication device to communicate the random accesssignal is further configured to receive, from the second wirelesscommunication device, the random access signal. In some embodiments,wherein the code for causing the first wireless communication device tocommunicate the random access configuration is further configured toreceive, from the second wireless communication device, the randomaccess configuration; the code for causing the first wirelesscommunication device to communicate the communication signal is furtherconfigured to receive, from the second wireless communication device,the communication signal; and the code for causing the first wirelesscommunication device to communicating the random access signal isfurther configured to transmit, to the second wireless communicationdevice, the random access signal based on a transmission power leveldetermined based on at least a reception power of the communicationsignal at the first wireless communication device and the transmissionpower level of the communication signal.

Embodiments of the present disclosure include an apparatus comprisingmeans for communicating, with a second wireless communication device, arandom access configuration including information associated with achannel characteristic difference between a first frequency spectrum anda second frequency spectrum, the random access configurationcommunicated in the first frequency spectrum; and means forcommunicating, with the second wireless communication device, a randomaccess signal in the second frequency spectrum based on the randomaccess configuration.

In some embodiments, wherein the channel characteristic differenceincludes at least one of a penetration loss difference between the firstfrequency spectrum and the second frequency spectrum, a path lossdifference between the first frequency spectrum and the second frequencyspectrum, or an antenna array gain difference between communications inthe first frequency spectrum and the second frequency spectrum. In someembodiments, wherein the means for communicating the random accessconfiguration is further configured to transmit, to the second wirelesscommunication device, the random access configuration, and wherein themeans for communicating the random access signal is further configuredto receive, from the second wireless communication device, the randomaccess signal. In some embodiments, the apparatus further comprisesmeans for determining a target reception power level of the randomaccess signal at the apparatus based on the channel characteristicdifference, wherein the random access configuration indicates the targetreception power level. In some embodiments, the apparatus furthercomprises means for determining an adjustment parameter for powercontrol at the second wireless communication device based on the channelcharacteristic difference, wherein the random access configurationindicates at least the adjustment parameter. In some embodiments,wherein the means for communicating the random access configuration isfurther configured to receive, from the second wireless communicationdevice, the random access configuration, and wherein the means forcommunicating the random access signal is further configured totransmit, to the second wireless communication device, the random accesssignal at a transmission power level based on the random accessconfiguration. In some embodiments, wherein the random accessconfiguration indicates a target reception power level at the secondwireless communication device, and wherein the apparatus furthercomprises means for determining the transmission power level based on atleast the target reception power level. In some embodiments, wherein therandom access configuration further indicates an adjustment parameterfor the channel characteristic difference, and wherein the means fordetermining the transmission power level is further configured todetermine the transmission power level further based on the adjustmentparameter. In some embodiments, the apparatus further comprising meansfor communicating, with the second wireless communication device, arandom access response in the first frequency spectrum in response tothe random access signal; means for communicating, with the secondwireless communication device, a connection request in the secondfrequency spectrum in response to the random access response; and meansfor communicating, with the second wireless communication device, aconnection response in the first frequency spectrum in response to theconnection request. In some embodiments, the apparatus further comprisesmeans for communicating, with the second wireless communication device,a first communication signal on a first subcarrier spacing in the firstfrequency spectrum; and means for communicating, with the secondwireless communication device, a second communication signal based on asecond subcarrier spacing in the second frequency spectrum, wherein thefirst subcarrier spacing and the second subcarrier spacing aredifferent. In some embodiments, wherein the first frequency spectrum isat a millimeter wave band. In some embodiments, wherein the secondfrequency spectrum is at a non-millimeter wave band.

Embodiments of the present disclosure include an apparatus comprisingmeans for communicating, with a second wireless communication device, arandom access configuration for a first frequency spectrum, the randomaccess configuration communicated in a second frequency spectrumdifferent from first frequency spectrum; means for communicating, withthe second wireless communication device, a communication signal in thefirst frequency spectrum based on the random access configuration; andmeans for communicating, with the second wireless communication device,a random access signal in the first frequency spectrum based on thecommunication signal.

In some embodiments, wherein the random access configuration indicatesat least a transmission power level of the communication signal, andwherein the communication signal includes at least one of asynchronization signal or a reference signal. In some embodiments,wherein the means for communicating the random access configuration isfurther configured to transmit, to the second wireless communicationdevice, the random access configuration; the means for communicating thecommunication signal is further configured to transmit, to the secondwireless communication device, the communication signal based on thetransmission power level; and the means for communicating the randomaccess signal is further configured to receive, from the second wirelesscommunication device, the random access signal. In some embodiments,wherein the means for communicating the random access configuration isfurther configured to receive, from the second wireless communicationdevice, the random access configuration; the means for communicating thecommunication signal is further configured to receive, from the secondwireless communication device, the communication signal; and the meansfor communicating the random access signal is further configured totransmit, to the second wireless communication device, the random accesssignal based on a transmission power level determined based on at leasta reception power of the communication signal at the apparatus and thetransmission power level of the communication signal.

As those of some skill in this art will by now appreciate and dependingon the particular application at hand, many modifications, substitutionsand variations can be made in and to the materials, apparatus,configurations and methods of use of the devices of the presentdisclosure without departing from the spirit and scope thereof. In lightof this, the scope of the present disclosure should not be limited tothat of the particular embodiments illustrated and described herein, asthey are merely by way of some examples thereof, but rather, should befully commensurate with that of the claims appended hereafter and theirfunctional equivalents.

What is claimed is:
 1. A method of wireless communication, comprising:communicating, by a first wireless communication device with a secondwireless communication device, a random access configuration for a firstfrequency spectrum, the random access configuration communicated in asecond frequency spectrum different from the first frequency spectrum,wherein the random access configuration includes a target receptionpower level for a random access signal based on channel characteristicdifferences between the first frequency spectrum and the secondfrequency spectrum; communicating, by the first wireless communicationdevice with the second wireless communication device, a communicationsignal in the first frequency spectrum based on the random accessconfiguration; and communicating, by the first wireless communicationdevice with the second wireless communication device, the random accesssignal in the first frequency spectrum based on the communication signaland the target reception power level for the random access signal. 2.The method of claim 1, wherein the random access configuration indicatesat least a transmission power level of the communication signal, andwherein the communication signal includes at least one of asynchronization signal or a reference signal.
 3. The method of claim 2,wherein: the communicating the random access configuration includestransmitting, by the first wireless communication device to the secondwireless communication device, the random access configuration; thecommunicating the communication signal includes transmitting, by thefirst wireless communication device to the second wireless communicationdevice, the communication signal based on the transmission power level;and the communicating the random access signal includes receiving, bythe first wireless communication device from the second wirelesscommunication device, the random access signal.
 4. The method of claim2, wherein: the communicating the random access configuration includesreceiving, by the first wireless communication device from the secondwireless communication device, the random access configuration; thecommunicating the communication signal includes receiving, by the firstwireless communication device from the second wireless communicationdevice, the communication signal; and the communicating the randomaccess signal includes transmitting, by the first wireless communicationdevice to the second wireless communication device, the random accesssignal based on an additional transmission power level determined basedon at least a reception power of the communication signal at the firstwireless communication device and the transmission power level of thecommunication signal.
 5. The method of claim 1, wherein: thecommunicating the random access configuration includes receiving, by thefirst wireless communication device from the second wirelesscommunication device, the random access configuration; the communicatingthe communication signal includes receiving, by the first wirelesscommunication device from the second wireless communication device, thecommunication signal; and the communicating the random access signalincludes transmitting, by the first wireless communication device to thesecond wireless communication device, the random access signal.
 6. Themethod of claim 1, wherein: the communicating the random accessconfiguration includes transmitting, by the first wireless communicationdevice to the second wireless communication device, the random accessconfiguration; the communicating the communication signal includestransmitting, by the first wireless communication device to the secondwireless communication device, the communication signal; and thecommunicating the random access signal includes receiving, by the firstwireless communication device from the second wireless communicationdevice, the random access signal.
 7. The method of claim 1, wherein thefirst frequency spectrum is at a millimeter wave band, and wherein thesecond frequency spectrum is at a non-millimeter wave band.
 8. Anapparatus comprising: a transceiver configured to: communicate, with asecond wireless communication device, a random access configuration fora first frequency spectrum, the random access configuration communicatedin a second frequency spectrum different from the first frequencyspectrum, wherein the random access configuration includes a targetreception power level for a random access signal based on channelcharacteristic differences between the first frequency spectrum and thesecond frequency spectrum; communicate, with the second wirelesscommunication device, a communication signal in the first frequencyspectrum based on the random access configuration; and communicate, withthe second wireless communication device, the random access signal inthe first frequency spectrum based on the communication signal and thetarget reception power level for the random access signal.
 9. Theapparatus of claim 8, wherein the random access configuration indicatesat least a transmission power level of the communication signal, andwherein the communication signal includes at least one of asynchronization signal or a reference signal.
 10. The apparatus of claim9, wherein the transceiver is further configured to: communicate therandom access configuration by transmitting, to the second wirelesscommunication device, the random access configuration; communicate thecommunication signal by transmitting, to the second wirelesscommunication device, the communication signal based on the transmissionpower level; and communicate the random access signal by receiving, fromthe second wireless communication device, the random access signal. 11.The apparatus of claim 9, wherein the transceiver is further configuredto: communicate the random access configuration by receiving, from thesecond wireless communication device, the random access configuration;communicate the communication signal by receiving, from the secondwireless communication device, the communication signal; and communicatethe random access signal by transmitting, to the second wirelesscommunication device, the random access signal.
 12. The apparatus ofclaim 8, wherein the transceiver is further configured to: communicatethe random access configuration by receiving, from the second wirelesscommunication device, the random access configuration; communicate thecommunication signal by receiving, from the second wirelesscommunication device, the communication signal; and communicate therandom access signal by transmitting, to the second wirelesscommunication device, the random access signal.
 13. The apparatus ofclaim 8, wherein the transceiver is further configured to: communicatethe random access configuration by transmitting, to the second wirelesscommunication device, the random access configuration; communicate thecommunication signal by transmitting, to the second wirelesscommunication device, the communication signal; and communicate therandom access signal by receiving, from the second wirelesscommunication device, the random access signal.
 14. The apparatus ofclaim 8, wherein the first frequency spectrum is at a millimeter waveband, and wherein the second frequency spectrum is at a non-millimeterwave band.
 15. A non-transitory computer-readable medium having programcode recorded thereon, the program code comprising: code for causing afirst wireless communication device to communicate, with a secondwireless communication device, a random access configuration for a firstfrequency spectrum, the random access configuration communicated in asecond frequency spectrum different from the first frequency spectrum,wherein the random access configuration includes a target receptionpower level for a random access signal based on channel characteristicdifferences between the first frequency spectrum and the secondfrequency spectrum; code for causing the first wireless communicationdevice to communicate, with the second wireless communication device, acommunication signal in the first frequency spectrum based on the randomaccess configuration; and code for causing the first wirelesscommunication device to communicate, with the second wirelesscommunication device, the random access signal in the first frequencyspectrum based on the communication signal and the target receptionpower level for the random access signal.
 16. The non-transitorycomputer-readable medium of claim 15, wherein the random accessconfiguration indicates at least a transmission power level of thecommunication signal, and wherein the communication signal includes atleast one of a synchronization signal or a reference signal.
 17. Thenon-transitory computer-readable medium of claim 16, wherein: the codefor causing the first wireless communication device to communicate therandom access configuration is further configured to transmit, to thesecond wireless communication device, the random access configuration;the code for causing the first wireless communication device tocommunicate the communication signal is further configured to transmit,to the second wireless communication device, the communication signalbased on the transmission power level; and the code for causing thefirst wireless communication device to communicate the random accesssignal is further configured to receive, from the second wirelesscommunication device, the random access signal.
 18. The non-transitorycomputer-readable medium of claim 16, wherein: the code for causing thefirst wireless communication device to communicate the random accessconfiguration is further configured to receive, from the second wirelesscommunication device, the random access configuration; the code forcausing the first wireless communication device to communicate thecommunication signal is further configured to receive, from the secondwireless communication device, the communication signal; and the codefor causing the first wireless communication device to communicate therandom access signal is further configured to transmit, to the secondwireless communication device, the random access signal.
 19. Thenon-transitory computer-readable medium of claim 15, wherein: the codefor causing the first wireless communication device to communicate therandom access configuration is further configured to receive, from thesecond wireless communication device, the random access configuration;the code for causing the first wireless communication device tocommunicate the communication signal is further configured to receive,from the second wireless communication device, the communication signal;and the code for causing the first wireless communication device tocommunicate the random access signal is further configured to transmit,to the second wireless communication device, the random access signal.20. The non-transitory computer-readable medium of claim 15, wherein:the code for causing the first wireless communication device tocommunicate the random access configuration is further configured totransmit, to the second wireless communication device, the random accessconfiguration; the code for causing the first wireless communicationdevice to communicate the communication signal is further configured totransmit, to the second wireless communication device, the communicationsignal; and the code for causing the first wireless communication deviceto communicate the random access signal is further configured toreceive, from the second wireless communication device, the randomaccess signal.